[Qemu-devel] [PATCH] target-s390x: Implement lpp instruction

[Qemu-devel] [PATCH] target-s390x: Implement lpp instruction

[Miroslav Benes]

Linux arch/s390/kernel/head(64).S uses lpp instruction if it is
available in facilities list provided by stfl/stfle instruction. This is
the case of newer z/System generations and their qemu definition.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
---
 target/s390x/insn-data.def |  2 ++
 target/s390x/translate.c   | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index be830a42ed8d..d6dd391fabeb 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -843,6 +843,8 @@
 /* LOAD CONTROL */
     C(0xb700, LCTL,    RS_a,  Z,   0, a2, 0, 0, lctl, 0)
     C(0xeb2f, LCTLG,   RSY_a, Z,   0, a2, 0, 0, lctlg, 0)
+/* LOAD PROGRAM PARAMETER */
+    C(0xb280, LPP,     S,   LPP,   0, m2_64, 0, 0, lpp, 0)
 /* LOAD PSW */
     C(0x8200, LPSW,    S,     Z,   0, a2, 0, 0, lpsw, 0)
 /* LOAD PSW EXTENDED */
diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 141167948ee8..eb9e13e59b7d 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -1194,6 +1194,7 @@ typedef enum DisasFacility {
     FAC_SCF,                /* store clock fast */
     FAC_SFLE,               /* store facility list extended */
     FAC_ILA,                /* interlocked access facility 1 */
+    FAC_LPP,                /* load-program-parameter */
 } DisasFacility;
 
 struct DisasInsn {
@@ -2567,6 +2568,15 @@ static ExitStatus op_lra(DisasContext *s, DisasOps *o)
     return NO_EXIT;
 }
 
+static ExitStatus op_lpp(DisasContext *s, DisasOps *o)
+{
+    check_privileged(s);
+    potential_page_fault(s);
+
+    tcg_gen_st_i64(o->in2, cpu_env, offsetof(CPUS390XState, pp));
+    return NO_EXIT;
+}
+
 static ExitStatus op_lpsw(DisasContext *s, DisasOps *o)
 {
     TCGv_i64 t1, t2;
-- 
2.11.0

Re: [Qemu-devel] [PATCH] target-s390x: Implement lpp instruction

[Richard Henderson]

On 02/25/2017 12:50 AM, Miroslav Benes wrote:
> Linux arch/s390/kernel/head(64).S uses lpp instruction if it is
> available in facilities list provided by stfl/stfle instruction. This is
> the case of newer z/System generations and their qemu definition.
>
> Signed-off-by: Miroslav Benes <mbenes@suse.cz>
> ---

I can't find LPP in my PoO 11th edition...

> +static ExitStatus op_lpp(DisasContext *s, DisasOps *o)
> +{
> +    check_privileged(s);
> +    potential_page_fault(s);
> +
> +    tcg_gen_st_i64(o->in2, cpu_env, offsetof(CPUS390XState, pp));

But you don't need the potential_page_fault, since this is not a store to guest 
memory.


r~

Re: [Qemu-devel] [PATCH] target-s390x: Implement lpp instruction

[Thomas Huth]

On 25.02.2017 00:51, Richard Henderson wrote:
> On 02/25/2017 12:50 AM, Miroslav Benes wrote:
>> Linux arch/s390/kernel/head(64).S uses lpp instruction if it is
>> available in facilities list provided by stfl/stfle instruction. This is
>> the case of newer z/System generations and their qemu definition.
>>
>> Signed-off-by: Miroslav Benes <mbenes@suse.cz>
>> ---
> 
> I can't find LPP in my PoO 11th edition...

LPP is one of the instructions that is documented separately.
You can find its spec here, for example:

http://www-01.ibm.com/support/docview.wss?uid=isg26fcd1cc32246f4c8852574ce0044734a

 Thomas

Re: [Qemu-devel] [PATCH] target-s390x: Implement lpp instruction

[Miroslav Benes]

On Sat, 25 Feb 2017, Richard Henderson wrote:

> On 02/25/2017 12:50 AM, Miroslav Benes wrote:
> > Linux arch/s390/kernel/head(64).S uses lpp instruction if it is
> > available in facilities list provided by stfl/stfle instruction. This is
> > the case of newer z/System generations and their qemu definition.
> > 
> > Signed-off-by: Miroslav Benes <mbenes@suse.cz>
> > ---
> 
> I can't find LPP in my PoO 11th edition...
> 
> > +static ExitStatus op_lpp(DisasContext *s, DisasOps *o)
> > +{
> > +    check_privileged(s);
> > +    potential_page_fault(s);
> > +
> > +    tcg_gen_st_i64(o->in2, cpu_env, offsetof(CPUS390XState, pp));
> 
> But you don't need the potential_page_fault, since this is not a store to
> guest memory.

Right. I got confused by Access Program Exception in the spec. Sending v2.

Thanks for the review!

Miroslav